Hi and thank you for your question! We usually recommend most patients start with two treatments of Halo. However, this can depend on several factors, including the issues to be treated and condition of the skin. For more severe issues more treatments may be needed. For maintenance, on average we would recommend one treatment a year, ideally. But again, this depends on the condition of the skin when starting treatment and the care of the skin in between treatments. If sun exposure is kept to a minimum and great products are used in the meantime, this will help maintain and enhance results. Also, if its being used as a preventative treatment less maintenance may be needed. Hope this helps! Best, Dr. Grant Stevens